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ARROYO LAGO RESIDENTIAL PROJECT ADDENDUM 188 FCS Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx c) Wastewater Treatment Capacity Would the project: Result in a determination by the wastewater treatment provider which serves or may serve the project that it has adequate capacity to serve the project’s projected demand in addition to the provider’s existing commitments? Prior FEIR Conclusions The Prior FEIR found that the County Project would construct its own on-site WWTP with a capacity to treat approximately 50,000 gpd. The Prior FEIR determined that this treatment capacity would have enough capacity to serve the proposed project’s expected wastewater generation, and no new or expanded wastewater treatment or conveyance facilities would be required beyond those provided in the County Project. The WWTP would be a membrane bioreactor treatment plant capable of producing disinfected tertiary recycled water as defined in California Code of Regulation, Title 22, Section 60301.230. Disinfected tertiary recycled water produced by the wastewater treatment facility would be stored in lined storage ponds and would be disposed of through irrigation of agricultural irrigation fields. The WWTP would be sized to meet the County Project’s needs and would not rely on external wastewater providers. Regulatory compliance with the RWQCB would be required. Therefore, the Prior FEIR concluded that impacts would be less than significant. (Draft EIR, pp. 3.17- 17, 6-22–6.24). Proposed Project Analysis and Conclusion Wastewater treatment and conveyance services for the proposed project would be provided by the City. As discussed above, the City owns and operates sanitary sewer lines throughout the City, and conveys wastewater to the DSRSD regional WWTP. Through a contract agreement with the City, DSRSD provides wastewater treatment services to the City. The proposed project would be expected to generate 27,677 gpd, which is less wastewater than the County Project’s estimated 32,667 gpd, given the nominal reduction in units.65 The DSRSD’s current WWTP has a maximum treatment capacity of 17 million gallons per day (mgd), with an average dry weather flow of 9.7 mgd. As such, consistent with the analysis in the Prior FEIR, it is anticipated that the wastewater generation rate for the proposed project would equate to only approximately 0.19 percent (or perhaps a bit less given the slight reduction in unit count) of the maximum treatment capacity of the WWTP. The DSRSD has observed that as water conservation measures have become more widely adopted, flow rates have not increased; however, the reduced flow has resulted in an increase in nutrient content loading that will be addressed through refinements to DSRSD’s treatment process. As part of its ongoing master planning process, DSRSD will identify actions that will need to be implemented to accommodate the increased loading generated by customers within its service area through the future planning horizon year (2050). Any identified changes to the DSRSD treatment process will be 65 Assumes wastewater generation is equivalent to 90 percent of water demand.